HHH-12917 Interning of strings for Filter definitions

hibernate-core/src/main/java/org/hibernate/internal/FilterHelper.java

@@ -14,6 +14,8 @@ import org.hibernate.internal.util.StringHelper;
 import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.sql.Template;
 
+import static org.hibernate.internal.util.StringHelper.safeInterning;
+
 /**
  * Implementation of FilterHelper.
  *
@@ -44,23 +46,27 @@ public class FilterHelper {
 		filterCount = 0;
 		for ( final FilterConfiguration filter : filters ) {
 			filterAutoAliasFlags[filterCount] = false;
-			filterNames[filterCount] = filter.getName();
-			filterConditions[filterCount] = filter.getCondition();
+			filterNames[filterCount] = safeInterning( filter.getName() );
+			filterConditions[filterCount] = safeInterning( filter.getCondition() );
 			filterAliasTableMaps[filterCount] = filter.getAliasTableMap( factory );
 			if ( ( filterAliasTableMaps[filterCount].isEmpty() || isTableFromPersistentClass( filterAliasTableMaps[filterCount] ) ) && filter
 					.useAutoAliasInjection() ) {
-				filterConditions[filterCount] = Template.renderWhereStringTemplate(
-						filter.getCondition(),
-						FilterImpl.MARKER,
-						factory.getDialect(),
-						factory.getSqlFunctionRegistry()
+				filterConditions[filterCount] = safeInterning(
+							Template.renderWhereStringTemplate(
+							filter.getCondition(),
+							FilterImpl.MARKER,
+							factory.getDialect(),
+							factory.getSqlFunctionRegistry()
+					)
 				);
 				filterAutoAliasFlags[filterCount] = true;
 			}
-			filterConditions[filterCount] = StringHelper.replace(
-					filterConditions[filterCount],
-					":",
-					":" + filterNames[filterCount] + "."
+			filterConditions[filterCount] = safeInterning(
+					StringHelper.replace(
+						filterConditions[filterCount],
+						":",
+						":" + filterNames[filterCount] + "."
+					)
 			);
 			filterCount++;
 		}

hibernate-core/src/main/java/org/hibernate/internal/util/StringHelper.java

@@ -886,4 +886,25 @@ public final class StringHelper {
 			return null;
 		}
 	}
+
+	/**
+	 * Return the interned form of a String, or null if the parameter is null.
+	 * <p>
+	 * Use with caution: excessive interning is known to cause issues.
+	 * Best to use only with strings which are known to be long lived constants,
+	 * and for which the chances of being actual duplicates is proven.
+	 * (Even better: avoid needing interning by design changes such as reusing
+	 * the known reference)
+	 * @param string The string to intern.
+	 * @return The interned string.
+	 */
+	public static String safeInterning(final String string) {
+		if ( string == null ) {
+			return null;
+		}
+		else {
+			return string.intern();
+		}
+	}
+
 }